可是看不懂啊,比如说这段: Error: 500 Location: /UPOS/Source/MenuDef.jsp Internal Servlet Error:javax.servlet.ServletException at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:459) at Source._0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6._jspService(_0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6.java:450) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.jasper.servlet.JspServlet$JspCountedServlet.service(JspServlet.java:130) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:282) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:429) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:500) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405) at org.apache.tomcat.core.Handler.service(Handler.java:287) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484)Root cause: java.lang.NullPointerException at Source._0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6._jspService(_0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6.java:209) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.jasper.servlet.JspServlet$JspCountedServlet.service(JspServlet.java:130) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:282) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:429) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:500) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405) at org.apache.tomcat.core.Handler.service(Handler.java:287) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) 这些出错在哪里呢?
这是空值的错误。有可能你对于null的字符类型进行了操作。
仔细找一下,看有没有什么对象还没有初始化或者值为null就对它进行了操作。
NullPointerException的错误是最不好找的,细心找找吧!
Root cause: java.lang.NullPointerException at Source._0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6._jspService(_0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6.java:209) at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.jasper.servlet.JspServlet$JspCountedServlet.service(JspServlet.java:130) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:282) at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:429) at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:500) at javax.servlet.http.HttpServlet.service(HttpServlet.java:853) at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405) at org.apache.tomcat.core.Handler.service(Handler.java:287) at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372) at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812) at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758) at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213) at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416) at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501) at java.lang.Thread.run(Thread.java:484) the sentence give ur a functin call ThreadPool.java/*source file name*/:501/*line number*/)
Error: 500
Location: /UPOS/Source/MenuDef.jsp
Internal Servlet Error:javax.servlet.ServletException
at org.apache.jasper.runtime.PageContextImpl.handlePageException(PageContextImpl.java:459)
at Source._0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6._jspService(_0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6.java:450)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspCountedServlet.service(JspServlet.java:130)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:282)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:429)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:500)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405)
at org.apache.tomcat.core.Handler.service(Handler.java:287)
at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812)
at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758)
at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213)
at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501)
at java.lang.Thread.run(Thread.java:484)Root cause:
java.lang.NullPointerException
at Source._0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6._jspService(_0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6.java:209)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspCountedServlet.service(JspServlet.java:130)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:282)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:429)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:500)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405)
at org.apache.tomcat.core.Handler.service(Handler.java:287)
at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812)
at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758)
at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213)
at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501)
at java.lang.Thread.run(Thread.java:484)
这些出错在哪里呢?
java.lang.NullPointerException
at Source._0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6._jspService(_0002fSource_0002fMenuDef_0002ejspMenuDef_jsp_6.java:209)
at org.apache.jasper.runtime.HttpJspBase.service(HttpJspBase.java:119)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspCountedServlet.service(JspServlet.java:130)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.jasper.servlet.JspServlet$JspServletWrapper.service(JspServlet.java:282)
at org.apache.jasper.servlet.JspServlet.serviceJspFile(JspServlet.java:429)
at org.apache.jasper.servlet.JspServlet.service(JspServlet.java:500)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:853)
at org.apache.tomcat.core.ServletWrapper.doService(ServletWrapper.java:405)
at org.apache.tomcat.core.Handler.service(Handler.java:287)
at org.apache.tomcat.core.ServletWrapper.service(ServletWrapper.java:372)
at org.apache.tomcat.core.ContextManager.internalService(ContextManager.java:812)
at org.apache.tomcat.core.ContextManager.service(ContextManager.java:758)
at org.apache.tomcat.service.http.HttpConnectionHandler.processConnection(HttpConnectionHandler.java:213)
at org.apache.tomcat.service.TcpWorkerThread.runIt(PoolTcpEndpoint.java:416)
at org.apache.tomcat.util.ThreadPool$ControlRunnable.run(ThreadPool.java:501)
at java.lang.Thread.run(Thread.java:484)
the sentence give ur a functin call
ThreadPool.java/*source file name*/:501/*line number*/)